Marshall Valvestate reverb problem

[Walter]

Hey guys,
This one has been driving me crazy all morning. I have a Valvestate VS100 head that I had to open up recently to do a little fixing in. Now that I have it back together I don't have any reverb. no reverb, no noise, nothing but clean guitar no matter what setting I put the knob to.
I read some previous posts and used the hum method to find which cable was the return for the verb and also checked to be sure that there was signal going down the drive cable. Everything is in order as far as I can tell. I then took the spring box out and looked in it to see if there were any open wires of anything of that nature. I am no expert but all looked good to me.
So any ideas on what to try next? I mean I know that signal is coming down the drive line, the hum tells me that the return is functional(?), and everything in the spring box looks a-o-k.
any tips on this or on the best way to glue my hair back to my head would be most appreciated

thanks again

[Enzo]

Disconnect the pan. Measure resistance at each jack. There is continuity or there is not. One end should be like 100-200 ohms or so, and the other anywhere from half an ohm to maybe 200. Open is bad, some relatively low resistance is good. The resistance won't be "wrong."

You can see broken wires, but as bad coil looks the same as a good coil - you can't tell by looking.

And are you sure the cables are plugged in th right ends?

[Walter]

I will definatly try checking the resistance. If it happens to be open then does that mean I need to replace the whole pan assembly?

Just for extra confirmation on this here is how I determined which way to hook up the pan:
with my amp and in the clean channel, I turned the clean reverb up to half way. I then touched the ends of each cable. The red one made a hum when I touched it so I plugged it in the output which was labled OUT on the top of the box. This left me with only one plug and one jack so I made an educated guess and plugged the plug into the jack.

For educational purposes what is the penalty for hooking up the reverb pan incorrectly??

[52 Bill]

I will definatly try checking the resistance. If it happens to be open then does that mean I need to replace the whole pan assembly?

Maybe, maybe not. Most problems are with the small wires that connect the transducer coils to the RCA jacks. Check each one for continuity, then check the transducer coils themselves by taking a reading at the small solder terminals at the coil ends. If you find that a coil is open, you could order a replacement from Accutronics, but by the time you pay for the part and spend an hour drilling out the rivets and then finding a nut and bolt to replace the coil, the easier method is to replace the entire tank.

For educational purposes what is the penalty for hooking up the reverb pan incorrectly??

In most cases no problems are caused by hooking up the tank backwards, but the reverb will usually not work, as the impedences are too far off for the circuit to work correctly. In some solid-state amps, where the in and output transducers are nearly the same, the reverb will work to some extent even if the tank is plugged in backwards.

[baddog]

keith

I have crate vc50 that had a reverb problem and it turned out to be the IC Chip in the reverb . My amp has a solid state reverb. I was getting a signal but it was really faint . It was a cheap fix but it kicked my ass until i figured it out with the help of ENZO THE GREAT

keith